The present invention relates to a water-proof structure for use with a frame body, in particular, this invention relates to a water-proof structure having a packing element. Such kind of a water-proof structure is effective when being used with a frame body which is usually installed in an outdoor environment.
In the past, a waterproof structure for use in protecting an equipment is a type as disclosed in Japanese Unexamined Patent Publication (JP-A) No. 17359 of 1992, which is constructed for the purpose of performing a water-cooling type of heat radiation for a semiconductor apparatus. FIGS. 1A and 1B are views schematically indicating an example of a water-proof structure made according to a prior art. In the drawings, a heat radiator 35 has a water path (now shown) which is formed to allow the flowing of water therethrough, so that the heat from a semiconductor within a cover 33 is allowed to conduct through a metal base 34 so as to be transferred to the outside. Further, the heat radiator 35 has a frame-like sealing element 31 secured on one surface thereof. Such a sealing element 31 has a certain elasticity so that the sealing element 31 itself may be pressingly secured on the cover 33 close to the lower edge projection 32 thereof formed along the lower edge of the cover 33. In this manner, a water drop 3A attached on the heat radiator 35 may be prevented from invading into the cover 33.
However, the above conventional waterproof structure has some problems in relation to a durability and external appearance, thus it is not suitable for use in a portable apparatus, nor is it appropriate to be used in an outdoor environment. As a result, such kind of a water-proof structure can not be used in the field of the present invention.
Further, another conventional water-proof structure for use in a portable apparatus or in an outdoor environment, is constructed by embedding a frame cover into a frame main body with a packing element interposed therebetween, so as to obtain a desired water-proof structure. FIGS. 2A and 2B are views schematically indicating an example of a waterproof structure involving the use of packing element. As shown in FIGS. 2A and 2B, this is a waterproof structure formed by embedding a frame cover 21 into a main frame body 22 with a packing element 24 interposed therebetween. In detail, a groove 23 having a square frame configuration is formed on the sealing edge portion of the main frame body 22, a packing element 24 having a similar square frame configuration is inserted in the groove 23, the cover 21 is then engaged on to the sealing edge portion of the main frame body 22. Finally, four screws 25 are used to fix the cover 21 on the main frame body 22, thereby obtaining and maintaining a desired water-proof structure. However, such a packing element 24 is apt to accidentally move out of the groove 23 when the cover 21 is closed on or taken off the main frame body 22. If the packing element 24 has left the groove 23, a desired water-proof property will be lost. In addition, another problem with the water-proof structure shown in FIGS. 2A and 2B is that an operation for the insertion of the packing element 24 into the groove 23 is relatively difficult.
On the other hand, a water-proof structure formed by interposing a packing element between the main frame body and the frame cover has been disclosed in Japanese Unexamined Patent Publication (JP-A) No. 31598 of 1983, Japanese Unexamined Utility Model Publication (JP-U) No. 94516 of 1991, and Japanese Unexamined Utility Model Publication (JP-U) No. 45479 of 1985, Japanese Unexamined Patent Publication (JP-A) No. 34467/1996, and Japanese Unexamined Utility Model Publication (JP-U) No. 13780 of 1985.
As discussed above, there are some problems associated with a water-proof structure involving the use of a packing element. A first problem is that, since a packing element is likely to be absorbed toward the frame cover when the frame cover is closed on or taken off the main frame body, causing the packing element to move away from the groove, resulting in a trouble that the packing element is only sandwiched between the main frame body and the frame cover, but losing a desired water-proof property. The loss of water-proof property is caused due to the following fact. Namely, the width of the groove formed on the sealing edge portion of the main frame body has a size including a packing width and a clearance. If the packing element has moved out of the groove and is simply sandwiched between the main frame body and the frame cover, a desired contact between the packing element and the groove wall will be lost, hence losing a desired water-proof property. Further, since the depth of the groove is less than the height of the packing element, a problem associated therewith is that the packing element is apt to move away from the groove. A second problem is that the packing element is difficult to be inserted into the groove formed on the sealing edge portion of the main frame body. Accordingly, an operation for assembling such a water-proof structure is hard to be performed with a high efficiency. As a result, there is a possibility that the packing element can be inserted into the groove with a wrong manner, making it difficult to maintain a desired water-proof property. A reason responsible for the second problem is that it is difficult to vertically insert the packing element into the groove formed on the sealing edge portion of the main frame body.